1. Field of the Invention
The present invention relates to a field emission device and a method for fabricating the same.
2. Description of the Related Art
FIG. 1 is a sectional view of a conventional field emission device. As shown in FIG. 1, a plurality of cathodes 2 are formed on a rear surface substrate 1 in the conventional field emission device. A plurality of microtips 2' are formed on the cathodes 2 in an array pattern. The microtips 2' are formed in a throughhole 3a of an insulating layer 3 formed on the cathodes 2. Gates 4 having an opening 4a corresponding to the throughhole 3a are stacked on the insulating layer 3. A front surface substrate 6 supported by spacers 8 spaced from each other by a predetermined distance is provided on the gates 4. A plurality of anodes 5 are formed on the front surface substrate 6 so as to be opposed to the microtips 2'. Red, green, and blue fluorescent films 7 are formed on the anodes 5 in strips. The microtip array of the rear surface substrate is a portion (refer to the portion in a circle in the drawing) corresponding to a cathode of an electron gun of a CRT. The portion coated by a fluorescent film of the front surface substrate is a portion corresponding to an anode formed on the front surface glass of a CRT.
When the microtip array of the field emission device is grounded and a uniform voltage is applied between the gates 4 and the anodes 5, electrons are emitted into a vacuum and arrive at the anodes 5. At this time, the electrons accelerated by the voltage of the anodes 5 collide with a fluorescent film 7 with a predetermined kinetic energy. The kinetic energy of the electrons is transmitted to the fluorescent film 7. The fluorescent film 7 receives the kinetic energy of the electrons and is excited. Accordingly, the fluorescent film 7 emits light. However, as shown in FIG. 1, since the red, green, and blue fluorescent films 7 are formed in parallel, spaced apart from each other by a predetermined distance, the frequency for driving the gates 4 becomes higher when the device is driven by switching the gates 4. Accordingly, signal processing becomes more difficult and the red, green, and blue fluorescent films 7 simultaneously emit light or are extinguished. Namely, the red, green, and blue fluorescent films cannot be driven in a way of emitting light individually. Also, the fluorescent films 7 can be fabricated using PVA-slurry or screen printing. A fluorescent material cannot be coated by an electrophoretic method. Therefore, it is expensive to fabricate the fluorescent film.